The present invention relates generally to systems for cooling and conditioning room air, and has particularly advantageous applications in textile mills and similar environments where the air temperature and/or humidity are higher, even significantly higher, than usual.
In the textile field, open-end spinning machines are becoming a dominant force in textile spinning operations. These open-end spinning machines include rotors and they are disposed to pull a significant quantity of room air through these rotors as part of the spinning process, and this air is exhausted back into the room, but only after its temperature has been increased dramatically during its passage through the rotors. In some typical open-end spinning machines, approximately 12-13 CFM of air is pulled through each rotor, and this air is heated approximately 48.degree. F., so that in a machine having 216 rotors, approximately 2700 CFM of air at a temperature of approximately 124.degree. F. is exhausted back into the room where the spinning machines are operating.
It is well-known that precise room conditions are required for producing spun yarn from open-end spinning machines, and the room temperature is usually maintained within the range of 74.degree.-80.degree. F. and relative humidity is maintained within the range of 58-62%.
It is a common pratice to capture the air discharged from open-end spinning machines, exhaust it to the outside, and intake an equivalent amount of cooler outside air through the air conditioning apparatus to reduce the energy consumption of the air conditioning system. While this practice is a somewhat effective energy reduction tactic, the air conditioning system must nevertheless be designed for a maximum peak refrigeration capacity that can handle the cooling and conditioning loads even in the most difficult hot and humid summer months when the enthalpy of the outside air is close to the enthalpy of the discharge air from the open-end spinning machines. This practice also at times creates an imbalance in exhausted air and intake air through the air conditioning apparatus and can cause infiltration of outside air directly into the conditioned spinning area, thereby adversely affecting the room conditions which must be maintained within close tolerances for optimum yarn production.
One of the most common conventional air conditioning systems used in textile mills is an air washer system in which air is taken from the room in which equipment is operating, and a portion of this air may be exhausted to the outside and the remainder mixed with incoming air from the outside as return air, such outside air being used only when it will reduce the required cooling and conditioning load imposed on the system. This return air is circulated through an air washer device where water is sprayed directly into the moving air simultaneously through one or more spray pipes to cool and/or control the humidity of the air. Sprayed water is collected in a reservoir and recycled by a pump to the spray pipe, and the inlet of this recycling pump is usually connected also to a source of chilled water with a control valve being used to vary the ratio of chilled water and recycled water fed to the pump inlet, the control valve operating in response to the sensed temperature of the conditioned air. The chilled water is cooled prior to its being fed to the inlet of the circulation pump by a conventional mechanical refrigeration unit that usually operates in conjunction with a cooling tower that is used as the final means of heat rejection.
The aforesaid conventional air washer systems have a cooling efficiency of about 80-90%, and while they can be designed or modified to provide the aforesaid significantly increased cooling and conditioning capacity required by the demands of open-end spinning operations, the capital costs are substantially increased by the additional mechanical refrigeration that is required and, importantly, the energy consumption and operating costs of the system as a whole are increased significantly because of the additional refrigeration equipment.
In accordance with the present invention, a cooling and conditioning system is provided which requires less refrigeration equipment to maintain the same room conditions as conventional systems, thereby resulting in a significant reduction in energy use and operating costs.